1. Field of the Invention
The present invention relates to apparatus for clamping and securing objects including, for example, saw blades. More particularly, the present invention relates to a saw blade clamping device for use in conjunction with a scroll saw and which allows a saw blade to be fastened to the saw without the need for significant adjustment by the operator.
2. Description of the Invention Background
Devices that hold or clamp an object in a desired orientation or in a desired position relative to other objects are necessary in many applications. For example, any sawing device incorporating an elongate saw blade having terminal ends typically includes a device for attaching at least one end of the saw blade to a portion of the saw that is selectively driven to reciprocate. Scroll saws and jigsaws, for example, many include a two-armed member or yoke that is generally C-shaped or U-shaped and that selectively reciprocates about a pivot point located at the yoke's rear or center region. A saw blade is connected between the free ends of the arms and cuts the workpiece as the yoke reciprocates.
When using a jig saw or scroll saw, it is often necessary to detach one or both ends of the saw blade from the saw. For example, worn or broken blades require replacement, one blade type or size may be replaced with another type or size for a specific application or during particular cutting operations, or one end of the blade may be detached from the machine so that the freed end may be passed through a bore in the workpiece. As such, the ease of operation of the clamping device connecting the saw blade to the saw becomes important.
A variety of clamping devices for connecting a saw blade to jig saws and scroll saws are known. For example, one basic device for attaching a saw blade to a scroll saw is in the form of a blade chuck that exerts clamping force on the blade through the threaded advancement of either a screw or a nut. FIG. 2 of U.S. Pat. No. 4,681,006, issued to Miller on Jul. 21, 1987, illustrates a device which clamps the end of the blade between the flat surface of a blade holder member, attached to the reciprocating arm, and a square nut threadedly attached to a threaded screw extending through a portion of the blade holder member. U.S. Pat. Nos. 2,099,321 and 1,964,651, issued to Tautz on Nov. 16, 1937 and Jun. 26, 1934, respectively, disclose a scroll saw blade chuck that secures the saw blade end through force exerted by tightening a thumbscrew against a wall of the chuck. FIGS. 9 and 10 of U.S. Pat. No. 1,877,705 issued on Sep. 13, 1932, to Tautz teach a scroll saw blade chuck including a horizontally extending socket head set screw threaded into the chuck body to place clamping pressure on jaws within the chuck.
The aforementioned existing designs require significant time to change or detach a blade and also require either the use of tools or the exertion of significant force to securely clamp the blade within the chuck. Changing a blade may be particularly difficult where, for example, the threads of the chuck's set screw are clogged or otherwise impaired, thus making rotation of the screw difficult.
Because the blade may need to be detached or replaced frequently, saw blade chucks that may be operated with little effort and that require little time in order to detach or replace saw blades provide distinct advantages. U.S. Pat. No. 5,363,733, issued to Baird et al. on Nov. 15, 1994, provides a saw blade chuck that may be quickly engaged and disengaged to secure and release an end of a saw blade. The elements of the chuck of the '733 patent are arranged so as to provide a mechanical advantage that magnifies the force applied by the operator to engage the clamp and secure the blade within the chuck. Although the chuck of the '733 patent provides distinct advantages over the known saw blade clamping devices, it must be manually engaged and disengaged from clamping the saw blade and it also must be manually adjusted to account for saw blades having different thicknesses.
Accordingly, the need exists for a saw blade clamp that will quickly and effectively attach saw blades of different thicknesses to sawing devices with minimal need for manipulation by the saw's operator. More generally, the need exists for improved clamping devices for objects not limited to saw blades, and that will clamp or secure such objects with little effort on the part of the operator and without the need for significant adjustment to account for variation in the dimensions of the various objects to be clamped.